The medical imaging apparatus is to provide a great deal of information about a subject through images, which plays an important role in many medical actions including disease diagnosis, medical treatment and surgical planning. At present, the major medical imaging apparatuses include ultrasonic diagnostic apparatuses, CT (computerized tomography) apparatuses, MRI (magnetic resonance imaging) apparatuses and nuclear medical diagnostic apparatuses. Among those, the magnetic resonance imaging apparatus is capable of acquiring images excellent in contrast for soft tissue, thus occupying an important position in the medical imaging diagnosis.
Imaging speed has advanced for the magnetic resonance imaging apparatus, allowing for taking successive images of three-dimensional data. Meanwhile, there is developed an art to take an image while moving a table top, enabling imaging over a broad range. Besides the intermittent imaging with the alternate repetition of imaging and movement, imaging is recently available with table-top continuous movement in X-ray CT. The three-dimensional imaging with table-top continuous movement is suitably applied in MRA (magnetic resonance angiography) with a contrast agent.
Meanwhile, there is a PI (parallel imaging) technique as one of high-speed imaging techniques based on the magnetic resonance imaging apparatuses. The PI technique captures images using an RF (radio frequency) coil that is structured as a multi-coil with a plurality of surface coils so that an NMR (nuclear magnetic resonance) signal can be received simultaneously at the surface coils and used in reconstructing an image.
With the PI technique, imaging time is to be reduced because the phase encode count (times) required for data acquisition for use in image reconstruction can be reduced by a factor corresponding to the number of surface coils. The PI technique is applicable together with 3D imaging and hence improved further in its performance.
Because a great deal of data processing is required for acquisition of data in a series of high-speed great-capacity imaging with traditional magnetic resonance imaging apparatus, there is difficulty in producing a three-dimensional image concurrent with data acquisition. For simple three-dimensional imaging, there is proposed a method to produce a two-dimensional image corresponding to a projection image, which is used as a monitor for an imaging result. However, such a method has not been proposed for three-dimensional imaging with continuous table-top movement.
Furthermore, where angiography is conducted on a subject by means of conventional magnetic resonance imaging apparatus using a contrast agent, there is a difficulty in setting up the table top in a position to follow the flow velocity of the contrast agent, and hence a difficulty in taking an image in a region within a field-of-view in a manner to follow the flow velocity of the contrast agent. This is because the flow velocity of the contrast agent differs from subject to subject and from region to region even on the same subject and thus, because of such broad possible ranges, table-top movement is not done at the contrast agent flow velocity. Consequently, data obtained by means of traditional magnetic resonance imaging apparatus often does not follow the contrast agent flow velocity and hence is not ideally suited for use in diagnosis.
Prior art documents related to the present application include the following.    Patent document 1: U.S. Pat. No. 5,631,560 description    Patent document 2: U.S. Pat. No. 5,166,875 description    Patent document 3: Japanese Patent No. 3,146,034    Patent document 4: U.S. Patent Application Publication No. 2006/0020198    Patent document 5: U.S. Pat. No. 6,912,415 description    Non-patent document 1: M. Sabati, M. L. Lauzon and R. Frayne; “Space-time relationship in continuously moving table method for large FOV peripheral contrast-enhanced magnetic resonance angiography*”; Phys Med Biol 2003 48: pages 2739-2752    Non-patent document 2: David G. Kruger, Stephen J. Riederer, Roger C. Grimm, and Phillip J. Rossman; “Continuously Moving Table Data Acquisition Method for Long FOV Contrast-Enhanced MRA and Whole-Body MRI”; Magnetic Resonance in Medicine 47: pages 224-231 (2002)    Non-patent Document 3: Yudong Zhu and Charles L. Dumoulin; “Extended Field-of-View Imaging With Table Translation and Frequency Sweeping”; Magnetic Resonance in Medicine 49: pages 1106-1112 (2003)    Non-patent Document 4: Stephan A. R. K.; “Parallel Imaging Continuously Moving Table MRI Using Moving RF Coils and In-place Sensitivity Calibration”; 2nd international work shop on P-MRI: 2004: page    Non-patent Document 5: M. O. Zenge, H. H. Quick, F. M. Vogt, M. E. Ladd; “MR Imaging with a Continuously Rolling Table Platform and High-Precision Position Feedback”; IS MRM 2004: page 2381    Non-patent Document 6: M. Ookawa, N. Ichinose, M. Miyazaki, I. Miyazaki, S. Sugiura; “One-Second Temporal Resolution 4D MR DSA with 3D TRICKS, Elliptical Centric View Ordering, and Parallel Imaging”; ISMRM 2003: page 324 (2003).